Just because the end concept was useless doesn’t mean the individual pieces don’t have value. Meta’s loose wallet probably kickstarted the work of dozens of smaller companies in the hardware space whose work can be parlayed into other areas.
It was not very efficient usage of the money. It actually ended up paying for overpriced real estate in the bay area and vanity toys such as Porsches.
That would be useful if they open sourced the effort. Otherwise it will die of total irrelevance 15-30 years from now.
Facebook's mismanagement of VR financed and launched Anduril.